Involvement in health risk behaviors is particularly salient during adolescence, which is not surprising given the specific developmental challenges faced during this time (for parents and adolescents). The primary aim of this research will be to assess, over time, how failure to negotiate key developmental challenges faced by adolescents drive some adolescents to become involved with peers who engage in health risk behaviors, in turn driving their own involvement in such behavior. It is hypothesized that involvement in health risk behavior will put the adolescent at risk for physical health problems. Several mediating and moderating models will be examined. The study will be conducted using a large sample (N=200) of court-referred adolescents (ages 11-16), both youth and parent report will be used. Obtaining this sample will significantly add to the existing research, for they are often understudied, particularly with respect to health issues, and will add to the understanding of a high risk population. The proposed developmental approach to understanding adolescent health risk behaviors has the potential to inform scientific understanding regarding the nature of adolescent, family, and peer roles in determining level and outcome of adolescent health risk behaviors.